"What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.

A molecule absorbed by eating red meat has been linked to inflammation and auto-immune illnesses. For him, being human is also about a single chemical that separates us from our closest relatives, and which could be linked to many of our most debilitating illnesses."

"What does it mean to be human? For most people, it all comes down to that extraordinary object between our ears, and how it blesses us with language, laughter and logic. But not for Ajit Varki, a doctor-cum-scientist who works in California.

A molecule absorbed by eating red meat has been linked to inflammation and auto-immune illnesses. For him, being human is also about a single chemical that separates us from our closest relatives, and which could be linked to many of our most debilitating illnesses."

Neanderthals, who shared this deficiency with us, ate 85% animal products in their diet. In modern Europeans animal products account for 14%. If this mutation appeared 3 million years ago in the time of Homo erectus, then why would it have a positive selection value? H. erectus was the first big game hunter. Death by arthritis or heart disease comes after the age of reproduction. The only positive selective value this gene could have,then, is to shorten the life span and so make room for the next generation. On the downside, all the knowledge carried by older people would be lost.

Neanderthals, who shared this deficiency with us, ate 85% animal products in their diet. In modern Europeans animal products account for 14%. If this mutation appeared 3 million years ago in the time of Homo erectus, then why would it have a positive selection value?

As all the problems that this molecule may possibly cause are all problems that only arise at an age almost no Homo Erectus or Neanderthal was ever going to reach, it would have no effective negative selective pressures. Assuming that there were any advantages apparent then it is easy to see why the mutation would have spread.

For the record, i'm dubious. It is interesting speculation, but i'm looking forward to hearing some more hard data.

As all the problems that this molecule may possibly cause are all problems that only arise at an age almost no Homo Erectus or Neanderthal was ever going to reach, it would have no effective negative selective pressures. Assuming that there were any advantages apparent then it is easy to see why the mutation would have spread.

For the record, i'm dubious. It is interesting speculation, but i'm looking forward to hearing some more hard data.

Well, taking only famous Neanderthals alone and from memory, La Chappelle aux Saints, Shandidar, Tabun 2, the Neander Valley holotype, Skhul 4 and 5, Krapina C&D, and La Ferrassie all reached middle age or older. I am sure there are many, many more lesser known finds.

Well, taking only famous Neanderthals alone and from memory, La Chappelle aux Saints, Shandidar, Tabun 2, the Neander Valley holotype, Skhul 4 and 5, Krapina C&D, and La Ferrassie all reached middle age or older. I am sure there are many, many more lesser known finds.

Cancers and other conditions that may or may not be associated with this molecule tend to become significant later in life that middle age. We're looking at mid fifties as a starting point. It's generally accepted that Neanderthals had a life expectancy of around thirty years.